Derivative Financial Instruments (Schedule of Offsetting of Derivative Assets) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Offsetting of Derivative Assets [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 1,116	$ 1,144
Derivative Asset, Fair Value, Gross Liability	0	0
Derivative Asset, Fair Value, Net	1,116	1,144
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	(503)	(1,144)
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	613	0
Barclays [Member]
Offsetting of Derivative Assets [Line Items]
Derivative Asset, Fair Value, Gross Asset	1,009	1,107
Derivative Asset, Fair Value, Gross Liability	0	0
Derivative Asset, Fair Value, Net	1,009	1,107
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	(503)	(1,107)
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	506	0
Wells Fargo Bank [Member]
Offsetting of Derivative Assets [Line Items]
Derivative Asset, Fair Value, Gross Asset	107	37
Derivative Asset, Fair Value, Gross Liability	0	0
Derivative Asset, Fair Value, Net	107	37
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	0	(37)
Derivative, Collateral, Obligation to Return Cash	0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral	$ 107	$ 0